Accurately and precisely determining a location of an ultrasonic emitter is useful in various technologies. For example, certain game systems include remote control units. A common type of remote control unit includes: a body which is gripped by a user; buttons, joysticks and/or other user-operable interface elements on the body; and hardware and software which generate and transmit commands corresponding to a user's manipulation of the interface elements to a console of the gaming system. Certain remote control units allow the user to transmit commands to the console by both manually manipulating the interface elements on the remote control unit and moving the remote control unit. Thus, accurately and precisely determining a location of an ultrasonic emitter on the remote control unit can allow a user of the associated gaming system to input commands to the console by moving the remote control unit.
Various obstacles and difficulties can make accurately and precisely determining the location of the ultrasonic emitter difficult. For example, piezoelectric ultrasonic transducers are generally very directional such that emissions from the piezoelectric ultrasonic transducer are stronger along one direction or axis and significantly weak along other directions. Changing a location or orientation of the piezoelectric ultrasonic transducer can significantly affect the strength of the emission directed towards the receiver. Thus, weaker emissions from the piezoelectric ultrasonic transducer may not be detected by the receiver if the location or orientation of the piezoelectric ultrasonic transducer is changed and a location measurement or calculation will be negatively affected.
Accordingly, a system for emitting a uniform ultrasonic signal would be useful. In particular, a system for emitting an omnidirectional ultrasonic signal would be useful.